camerapediafandomcom-20200215-history
Camera
A camera is little more than a light-tight box containing some image recording media (usually film or digital sensor) with a shutter to control exposure of that media to light. etymology Camera is an abbreviation of camera obscura (latin for dark chamber), mainly known as a facility for landscape drawers in the 18th century. The camera obscura had a lens/mirror optics as light opening, the "media" in the camera was the painter who traced with his pencil the contours of the image projected onto his white paper sheet. The abbreviated term camera caught on with the spreading of photochemical imaging around 1840. Anatomy of a Camera (this part of the article needs to be reworked) media The media to be exposed to light is contained inside the camera or the camera back. If not in the camera back the camera includes a film load system, or instead a digital sensor combined with a digital image data storage. Some digital cameras allow no exchange of memory module. Then they must have an electronic data transfer interface to make image data accessible. Back Older film camera's backs have windows to show the exposure number, newer ones have a window to show the presence of a film cartridge. Some cameras - especially medium format and large format cameras - have interchangeable backs. Some backs allow continuous shooting on very long film rolls, or with film plate magazines. They also make it possible to use different film formats. Some cameras have backs available for everything from 35mm to 6x6 to 8x10 film or digital sensor. Some cameras give the choice of using the internal film load system or that of an alternate camera back. Some cameras need steady exchange of focusing screen and film plate frame, that means partial exchange of the back for each exposure. Frame The part of film or the photographic glass plate to be exposed next is usually in a fixed position. The glass plates need the frame to be fixed, the film rolls need a frame that delimits the area on the film to be used for one exposure. The part of film to be exposed next lies stretched directly behind the frame, positioned exactly in the image plane. Frame Counter A frame counter is a mechanism for recording the number of film frames exposed or for calculating the number of exposures remaining on a roll of film or memory card. Light opening A camera has at least a little round hole to let in light. Better imaging results are achieved by designing that opening a little larger and mounting a lens into it. Then the lens is the camera's light opening. The lens can be part of the camera, or it is accessory for camera systems with exchangeable lenses. Shutter The shutter is the mechanism that opens and closes at specified intervals in order to allow light to pass through the lens (or through the hole of a pinhole camera). The three most common types of shutter are guillotine shutter, leaf shutter and focal plane shutter. In the early days of photography exposure times had been so long that cameras needed no other shutter than the lens cover. Viewfinder The viewfinder is the part of the camera that indicates, either optically or electronically, what will appear in the field of view of the lens. In most cases this is a glass window you look through to compose, but in some cases in can be as simple as one or more wire frames you use to approximate your field of view. Many of today's point-and-shoot digicams have omitted the optical viewfinder and use an LCD screen on the back of the camera as its viewfinder. A diopter adjustment is an optical adjustment on the viewfinder of a camera that allows someone to adjust the viewfinder's magnification to their vision, removing the need to wear eyeglasses when looking through it. Diopter adjustments cannot compensate for all vision problems, only near and far sightedness can be compensated. Modern Camera features TTL Metering TTL or through the lens metering is a method of metering in which a camera's built-in light meter reads the light coming through the lens. This is considered to be more accurate because the light meter only sees the light that will hit the focal plane and other ambient light conditions can't "fool" the meter. Autoexposure Cameras with auto-exposure are able to set the shutter speed, the aperture, or both automatically based on the meter reading. Center-Weighted Center-weighted light-meters favor the center of the frame, while taking into account the rest of the frame to a lesser extent. Autofocus Autofocus cameras are able to adjust the lens electronically in order to get your desired subject "in focus".